Roblox Plus doesn't give back 500 Robux?

So first of all Moin guys,

The matter is complicated, but I would like to briefly introduce you to what happened, namely: I wanted to send Robux to my brother because I hardly play Roblox anymore. With Roblox Plus I wanted to send up to 500 Robux, so far, so good, but then, after I had sent the whole thing, I had to enter an e-mail from a parent, and there I entered mine, and when reading through then Roblox wanted me to sign up on a parent account, what the hell? I quickly did all the poop with Face ID, but the thing is: I'm still 17 today and I can't do the whole thing. Then I wanted to leave the trash after 30 minutes of wasted life and give my brother my account, But now just 500 Robux are missing, which none of us owns both.

My question now would be:

1. Will I get my Robux back within 24 hours?

2. Can I do this without a parent account once I'm 18 on Roblox?